Continuously variable transmission with chain output

ABSTRACT

A multi-mode continuously variable transmission in a powertrain of a motor vehicle includes a continuously variable unit connected to a planetary gear set arrangement. The planetary gear set arrangement generally includes two planetary gear sets, two brakes, and one clutch and provides multiple modes of ratio selection between the continuously variable unit and a transmission output member. The transmission output member is connected to a chain driven final having only three axes of rotation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Non-Provisional applicationSer. No. 14/321,084 filed Jul. 1, 2014 which claims benefit of U.S.Provisional Application No. 61/842,630 filed Jul. 3, 2013. Thedisclosure of the above applications are incorporated herein byreference.

FIELD

The present disclosure relates to automatic transmissions and moreparticularly to a continuously variable transmission having a chainoutput.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A continuously variable transmission (“CVT”) typically includes a beltand pulley system that operatively couples a rotary power source, suchas an engine or electric motor, to a double gear final drive unit. Thebelt and pulley system generally includes first and second pairs ofpulley cones having a torque transmitting belt or chain extendingbetween the cone pairs. Each pulley cone pair includes an axiallystationary pulley member and an axially movable pulley member. Eachmovable pulley member is axially adjustable with respect to thestationary pulley member by a hydraulic system. The hydraulic systemprovides primary and secondary hydraulic pressures to the respectivemovable pulley members to adjust the running radius of the first andsecond pulley cone pairs which in turn controls the output/input ratioof the continuously variable transmission. Movement of the conessteplessly or continuously varies the ratio of an input speed to anoutput speed. With the continuously variable transmission, small buteffective ratio changes can be attained. This is in contrast to a fixedgear ratio unit where any ratio changes are step values.

CVT axial length and mass significantly impact its power density andefficiency. Accordingly, there is a constant need for improved CVTdesigns that minimize axial length and mass while providing sufficientperformance characteristics.

SUMMARY

A powertrain for a motor vehicle is provided. The powertrain includes acontinuously variable transmission having a continuously variable unitconnected to a planetary gear set arrangement. The planetary gear setarrangement generally includes two planetary gear sets, two brakes, andone clutch and provides multiple modes of ratio selection between thecontinuously variable unit and a transmission output member. Thetransmission output member is connected to a chain driven final havingonly three axes of rotation.

In one aspect of the present invention, a powertrain for a motor vehicleincludes a transmission input member, a transmission output member, acontinuously variable unit having a first pulley pair connected forcommon rotation with the transmission input member, a second pulleypair, and an endless member wrapped around the first pulley pair and thesecond pulley pair, a first planetary gear set having a plurality ofmembers, and a second planetary gear set having a plurality of members,wherein the second planetary gear set is connected for common rotationto the first planetary gear set, the continuously variable unit, and thetransmission output member. A clutch selectively connects for commonrotation the first planetary gear set to the second planetary gear set.A first brake selectively connects the first planetary gear set to astationary member. A second brake selectively connects the secondplanetary gear set to the stationary member. A chain drive is connectedfor common rotation with the transmission output member. A transfermember is connected for common rotation with the chain drive. A finaldrive planetary gear set is connected for common rotation with thetransfer member. The powertrain includes only three axes of rotationfrom the transmission output member to the final drive planetary gearset.

In another aspect of the present invention, the first planetary gear setincludes a first member, a second member, and a third member and thesecond planetary gear set includes a first member, a second member, anda third member, wherein the first member of the first planetary gear setis connected for common rotation with the second member of the secondplanetary gear set, and the second member of the first planetary gearset is connected for common rotation with the third member of the secondplanetary gear set.

In another aspect of the present invention, the first member of thesecond planetary gear set is connected for common rotation with thesecond pulley pair and the second member of the first planetary gear setand the third member of the second planetary gear set are connected forcommon rotation with the transmission output member.

In another aspect of the present invention, the clutch selectivelyconnects for common rotation the first member of the first planetarygear set and the second member of the second planetary gear set to thesecond member of the first planetary gear set and the third member ofthe second planetary gear set.

In another aspect of the present invention, the first brake selectivelyconnects the first member of the first planetary gear set and the secondmember of the second planetary gear set to the stationary member.

In another aspect of the present invention, the second brake selectivelyconnects the third member of the first planetary gear set to thestationary member.

In another aspect of the present invention, the first member of thefirst planetary gear set and the second member of the second planetarygear set are integrally formed as a single rotating member.

In another aspect of the present invention, the second member of thefirst planetary gear set and the third member of the second planetarygear set are integrally formed as a single rotating member.

In another aspect of the present invention, the first member of thefirst planetary gear set is a ring gear, the second member of the firstplanetary gear set is a planet carrier member, the third member of thefirst planetary gear set is a sun gear, the first member of the secondplanetary gear set is a sun gear, the second member of the secondplanetary gear set is a ring gear, and the third member of the secondplanetary gear set is a planet carrier member.

In another aspect of the present invention, the second member of thefirst planetary gear set and the third member of the second planetarygear set both support a plurality of stepped pinions and a plurality ofpinions, wherein each of the plurality of stepped pinions have a firstportion in mesh with the third member of the first planetary gear setand a second portion in mesh with the integrally formed first member ofthe first planetary gear set and the second member of the secondplanetary gear set and in mesh with the plurality of pinions, andwherein the plurality of pinions are in mesh with the first member ofthe second planetary gear set.

In another aspect of the present invention, the final drive planetarygear set includes a first member, a second member, and a third member,wherein the first member is connected for common rotation with thetransfer member, the second member is interconnected to road wheels ofthe motor vehicle, and the third member is connected to the stationarymember.

In another aspect of the present invention, the first member of thefinal drive planetary gear set is a sun gear, the second member of thefinal drive planetary gear set is a planet carrier member, and the thirdmember of the final drive planetary gear set is a ring gear.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and isnot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a schematic diagram of a powertrain according to theprinciples of the present invention;

FIG. 2A is a schematic lever diagram of an exemplary transmissionaccording to the principles of the present invention;

FIG. 2B is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 2C is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 2D is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 2E is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 2F is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 3A is a diagrammatic illustration of an embodiment of atransmission according to the principles of the present invention;

FIG. 3B is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 3C is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 3D is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 3E is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 3F is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 4A is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 4B is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 4C is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 4D is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 4E is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 4F is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 5A is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 5B is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 5C is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 5D is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 5E is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 5F is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 6A is a schematic lever diagram of an exemplary transmissionaccording to the principles of the present invention;

FIG. 6B is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 6C is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 6D is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 6E is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 6F is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 7A is a diagrammatic illustration of an embodiment of atransmission according to the principles of the present invention;

FIG. 7B is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 7C is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 7D is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 7E is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 7F is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 8A is a schematic lever diagram of an exemplary transmissionaccording to the principles of the present invention;

FIG. 8B is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 8C is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 8D is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 8E is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 8F is a schematic lever diagram of another exemplary transmissionaccording to the principles of the present invention;

FIG. 9A is a diagrammatic illustration of an embodiment of atransmission according to the principles of the present invention;

FIG. 9B is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 9C is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 9D is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention;

FIG. 9E is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention; and

FIG. 9F is a diagrammatic illustration of another embodiment of atransmission according to the principles of the present invention.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

With reference to FIG. 1, a powertrain for a motor vehicle is generallyindicated by reference number 10. The powertrain 10 generally includesan engine 12 interconnected with a transmission 14. The engine 12 may bea conventional gasoline, Diesel, or flex fuel internal combustionengine, a hybrid engine, or an electric motor, or any other type ofprime mover, without departing from the scope of the present disclosure.The engine 12 supplies a driving torque to the transmission 14 through,for example, a flexplate (not shown) or other connecting device or astarting device 15 such as a hydrodynamic device or launch clutch.

The transmission 14 is a variable diameter pulley or sheave drivecontinuously variable transmission (CVT). The transmission 14 includes atypically cast, metal housing 16 which encloses and protects the variouscomponents of the transmission 14. The housing 16 includes a variety ofapertures, passageways, shoulders and flanges which position and supportthese components. Generally speaking, the transmission 14 includes atransmission input shaft 20 and a transmission output shaft 22.Connected between the transmission input shaft 20 and the transmissionoutput shaft 22 is a pulley assembly 24 and a gearbox 26 that cooperateto provide forward and reverse speed or gear ratios between thetransmission input shaft 20 and the transmission output shaft 22. Thetransmission input shaft 20 is functionally interconnected with theengine 12 through the starting device 15 and receives input torque orpower from the engine 12. The transmission output shaft 22 is preferablyconnected with a chain driven final drive unit 28. The transmissionoutput shaft 22 provides drive torque to the final drive unit 28.

The transmission input shaft 20 is connected to the pulley assembly 24.The pulley assembly 24 includes a first pulley or sheave pair 30 and asecond pulley or sheave pair 32. The first pulley 30 includes a firsttruncated conical sheave or member 30A and second truncated conicalsheave or member 30B in axial alignment with the first truncated conicalsheave 30A. The second sheave 30B is directly connected for rotationwith the transmission input member 20 and may be integrally formed withthe transmission input member 20. The first sheave 30A is moveableaxially relative to the second sheave 30B by a hydraulic control system(not shown) or other actuating system. It should be appreciated that thesheaves 30A and 30B may be axially switched without departing from thescope of the present invention.

The second pulley 32 includes a first truncated conical sheave or member32A and second truncated conical sheave or member 32B in axial alignmentwith the first truncated conical sheave 32A. The second sheave 32B isdirectly connected for rotation with a transfer shaft or member 34 ormay be integrally formed with the transfer shaft 34. The first sheave32A is moveable axially relative to the second sheave 32B by a hydrauliccontrol system (not shown) or other actuating system. It should beappreciated that the sheaves 32A and 32B may be axially switched withoutdeparting from the scope of the present invention.

A torque transmitting belt or chain 36 having a V-shaped cross sectionis mounted between the first pulley pair 30 and the second pulley pair32. Drive torque communicated from the transmission input shaft 20 istransferred via friction between the sheaves 30A and 30B and the belt36. The ratio of the input pulley 30 to the output pulley 32 is adjustedby varying the spacing between the sheaves 30A and 30B and between thesheaves 32A and 32B. For example, to change the ratio between thepulleys 30 and 32, the axial distance between sheaves 30A and 30B may bereduced by moving sheave 30A towards sheave 32B while simultaneously theaxial distance between sheave 32A and 32B may be increased by movingsheave 32A away from sheave 32B. Due to the V-shaped cross section ofthe belt 36, the belt 36 rides higher on the first pulley 30 and loweron the second pulley 32. Therefore the effective diameters of thepulleys 30 and 32 change, which in turn changes the overall gear ratiobetween the first pulley 30 and the second pulley 32. Since the radialdistance between the pulleys 30 and 32 and the length of the belt 36 isconstant, the movement of the sheaves 30A and 32A must occursimultaneously in order to maintain the proper amount of tension on thebelt 36 to assure torque is transferred from the pulleys 30, 32 to thebelt 36.

The pulley assembly 24 transfers torque to the gearbox 26 via thetransfer shaft 34. The gearbox 26 comprises one of several planetarygear set transmissions or arrangements, as will be described in greaterdetail below. The gearbox 26 outputs torque from the pulley assembly 26to the transmission output shaft 22.

The transmission output shaft 22 is interconnected with or includes afirst spur gear or drive sprocket 38. A transfer chain 40 is engaged orotherwise meshed with the drive sprocket 38 and engaged or otherwisemeshed with a second spur gear or driven sprocket 42. The drivensprocket 42 is interconnected with a final drive planetary gear set 44either directly or via a shaft or member 46.

The final drive planetary gear set 44, as well as the various gearbox 26arrangements described below, are illustrated in a lever diagram format.A lever diagram is a schematic representation of the components of amechanical device such as an automatic transmission. Each individuallever represents a planetary gear set wherein the three basic mechanicalcomponents of the planetary gear are each represented by a node.Therefore, a single lever contains three nodes: one for the sun gear,one for the planet gear carrier, and one for the ring gear. In somecases, two levers may be combined into a single lever having more thanthree nodes (typically four nodes). For example, if two nodes on twodifferent levers are interconnected through a fixed connection they maybe represented as a single node on a single lever. The relative lengthbetween the nodes of each lever can be used to represent the ring-to-sunratio of each respective gear set. These lever ratios, in turn, are usedto vary the gear ratios of the transmission in order to achieve anappropriate ratios and ratio progression. Mechanical couplings orinterconnections between the nodes of the various planetary gear setsare illustrated by thin, horizontal lines and torque transmittingdevices such as clutches and brakes are presented as interleavedfingers. Further explanation of the format, purpose and use of leverdiagrams can be found in SAE Paper 810102, “The Lever Analogy: A NewTool in Transmission Analysis” by Benford and Leising which is herebyfully incorporated by reference.

For example, the final drive planetary gear set 44 includes a first node44A, a second node 44B, and a third node 44C. The first node 44A iscoupled to the driven sprocket 42. The third node 44C is connected to afixed or stationary member such as the transmission housing 14. Thesecond node 44B is a final drive member that may be interconnected to adifferential, drive axles, and vehicle road wheels. In a preferredembodiment, the first node 44A corresponds to a sun gear, the secondnode 44B corresponds to a planet carrier member, and the third node 44Ccorresponds to a ring gear. Thus, the powertrain 10 only includes threeoutput axes for drive torque: transmission output shaft 22, shaft 46,and the final drive member or planet carrier 44B. By eliminating theconventional four axis arrangement and having only three axes, thepowertrain 10 has greater packaging flexibility since elimination of thefourth axis allows greater flexibility and space to package the shaft46.

Turning now to FIGS. 2A-F, various configurations of the gearbox 26 areshown in lever diagram format. The gearboxes illustrated in FIGS. 2A-Finclude specific types of transmissions known as Ravigneaux, powerglide,and RC-RC levers, as will be described below. The gearbox or planetarygear arrangement 26 includes a first planetary gear set 50 and a secondplanetary gear set 52. The first planetary gear set 50 has three nodes:a first node 50A, a second node 50B and a third node 50C. The secondplanetary gear set 52 has three nodes: a first node 52A, a second node52B and a third node 52C.

The transfer member 34 is continuously coupled to the first node 52A ofthe second planetary gear set 52. The transmission output member 22 iscoupled to the third node 52C of the second planetary gear set 52. Thefirst node 50A of the first planetary gear set 50 is coupled to thesecond node 52B of the second planetary gear set 52. The second node 50Bof the first planetary gear set 50 is coupled to the third node 52C ofthe second planetary gear set 52.

A first brake 54 selectively connects the second node 52B of the secondplanetary gear set 52 and the first node 50A of the first planetary gearset 50 with a stationary element or transmission housing 14. A secondbrake 56 selectively connects the third node 50C of the first planetarygear set 50 with the stationary element or transmission housing 14. Afirst clutch 58 selectively connects the first node 50A of the firstplanetary gear set 50 and the second node 52B of the second planetarygear set 52 with the third node 50C of the first planetary gear set 50.

With reference to FIG. 2B, an alternate gearbox arrangement 26B isshown. The gearbox 26B is similar to that shown in FIG. 2A and thereforelike components are indicated by like reference numbers. However, inFIG. 2B, the first clutch 58 is relocated and selectively connects thefirst node 50A of the first planetary gear set 50 and the second node52B of the second planetary gear set 52 with the second node 50B of thefirst planetary gear set 50 and the third node 52C of the secondplanetary gear set 52.

With reference to FIG. 2C, an alternate gearbox arrangement 26C isshown. The gearbox 26C is similar to that shown in FIG. 2A and thereforelike components are indicated by like reference numbers. However, inFIG. 2C, the first clutch 58 is relocated and selectively connects thesecond node 50B of the first planetary gear set 50 and the third node52C of the second planetary gear set 52 with the third node 50C of thefirst planetary gear set 50.

With reference to FIG. 2D, an alternate gearbox arrangement 26D isshown. The gearbox 26D is similar to that shown in FIG. 2A and thereforelike components are indicated by like reference numbers. However, inFIG. 2D, the first clutch 58 is relocated and selectively connects thefirst node 50A of the first planetary gear set 50 and the second node52B of the second planetary gear set 52 with the first node 52A of thesecond planetary gear set 52.

With reference to FIG. 2E, an alternate gearbox arrangement 26E isshown. The gearbox 26E is similar to that shown in FIG. 2A and thereforelike components are indicated by like reference numbers. However, inFIG. 2E, the first clutch 58 is relocated and selectively connects thesecond node 50B of the first planetary gear set 50 and the third node52C of the second planetary gear set 52 with the first node 52A of thesecond planetary gear set 52.

With reference to FIG. 2F, an alternate gearbox arrangement 26F isshown. The gearbox 26F is similar to that shown in FIG. 2A and thereforelike components are indicated by like reference numbers. However, inFIG. 2F, the first clutch 58 is relocated and selectively connects thefirst node 52A of the second planetary gear set 52 with the third node50C of the first planetary gear set 50.

Turning now to FIGS. 3A-F stick diagrams present schematic layouts ofembodiments of the gearbox 26, 26B-F according to the present invention.In FIGS. 3A-F the numbering from the lever diagram of FIGS. 2A-F arecarried over. The clutches and couplings are correspondingly presentedwhereas the nodes of the planetary gear sets now appear as components ofplanetary gear sets such as sun gears, ring gears, planet gears andplanet gear carriers.

For example, the gear sets 50 and 52 include a common planet carriermember 50B/52C, a ring gear member 50A, a sun gear member 50C, and a sungear member 52A. It should be appreciated that ring gear member 52B isoptional. The common planet carrier member 50B/52C rotatably supports aset of planet gears 50D (only one of which is shown) and 52D (only oneof which is shown). The planet gears 50D are each configured tointermesh with the ring gear member 50A while the planet gears 52D arelong pinions that each intermesh with both the planet gears 50D and thesun gear member 52A. The sun gear member 50C is connected for commonrotation with a first shaft or interconnecting member 60. The sun gearmember 52A is connected for common rotation with the transfer member 34.The planet carrier member 50B/52C is connected for common rotation withthe transmission output shaft 22. The ring gear member 50A is connectedfor common rotation with a second shaft or interconnecting member 62.

The torque-transmitting mechanisms or brakes 54, 56 and clutch 58 allowfor selective interconnection of the shafts or interconnecting members,members of the planetary gear sets and the housing. Thetorque-transmitting mechanisms are friction, dog or synchronizer typemechanisms or the like. For example, the first brake 54 is selectivelyengageable to connect the second shaft or interconnecting member 62 withthe transmission housing 14 in order to restrict relative rotation ofthe member 62 and therefore the ring gear member 50A. The second brake56 is selectively engageable to connect the first shaft orinterconnecting member 60 with the transmission housing 14 in order torestrict relative rotation of the member 60 and therefore the sun gearmember 50C. In FIG. 3A, the clutch 58 is selectively engageable toconnect the ring gear member 50A with the sun gear member 50C. Likewise,FIGS. 3B-3F illustrate stick diagrams of the corresponding gearboxarrangements 26B-26F which alter the location of the clutch 58, asdescribed above.

Turning now to FIGS. 4A-F stick diagrams present schematic layouts ofRavigneaux type embodiments of the gearbox 26, 26B-F according to thepresent invention. In FIGS. 4A-F the numbering from the lever diagram ofFIGS. 2A-F are carried over. The clutches and couplings arecorrespondingly presented whereas the nodes of the planetary gear setsnow appear as components of planetary gear sets such as sun gears, ringgears, planet gears and planet gear carriers.

For example, the planetary gear set 50 is configured as a simpleplanetary gear set while planetary gear set 52 is a compound planetarygear set. The gear sets 50 and 52 include a common planet carrier member50B/52C, a common ring gear member 50A/52B, a first sun gear member 50C,and a second sun gear member 52A. The common planet carrier member50B/52C rotatably supports a set of planet gears or stepped pinions 50D(only one of which is shown) and planet gear or non-stepped pinions 52D(only one of which is shown). The planet gears 50D are each configuredto intermesh with both the sun gear member 50C and the ring gear member50A/52B. The planet gears 50D are stepped pinions having a first steppedportion 51 and a second stepped portion 53. The planet gears 52D eachintermesh with both the stepped portions 53 of the planet gears 50D andthe sun gear member 52A. The sun gear member 50C is connected for commonrotation with a first shaft or interconnecting member 60. The sun gearmember 52A is connected for common rotation with the transfer member 34.The planet carrier member 50B/52C is connected for common rotation withthe transmission output shaft 22. The ring gear member 50A/52B isconnected for common rotation with a second shaft or interconnectingmember 62.

The first brake 54 is selectively engageable to connect the second shaftor interconnecting member 62 with the transmission housing 14 in orderto restrict relative rotation of the member 62 and therefore the ringgear member 50A/52B. The second brake 56 is selectively engageable toconnect the first shaft or interconnecting member 60 with thetransmission housing 14 in order to restrict relative rotation of themember 60 and therefore the sun gear member 50C. In FIG. 4A, the clutch58 is selectively engageable to connect the ring gear member 50A/52Bwith the sun gear member 50C. Likewise, FIGS. 4B-4F illustrate stickdiagrams of the corresponding gearbox arrangements 26B-26F which alterthe location of the clutch 58, as described above.

Turning now to FIGS. 5A-F stick diagrams present schematic layouts ofembodiments of the gearbox 26, 26B-F according to the present invention.In FIGS. 5A-F the numbering from the lever diagram of FIGS. 2A-F arecarried over. The clutches and couplings are correspondingly presentedwhereas the nodes of the planetary gear sets now appear as components ofplanetary gear sets such as sun gears, ring gears, planet gears andplanet gear carriers.

For example, the planetary gear set 50 includes a sun gear member 50C, aring gear member 50A, and a planet carrier member 50B that rotatablesupports a set of planet gears 50D (only one of which is shown). Theplanet gears 50D are each configured to intermesh with both the sun gearmember 50C and the ring gear member 50A. The sun gear member 50C isconnected for common rotation with the first shaft or interconnectingmember 60. The ring gear member 50A is connected for common rotationwith the second shaft or interconnecting member 62. The planet carriermember 50B is connected for common rotation with the transmission outputshaft 22.

The planetary gear set 52 includes a sun gear member 52A, a ring gearmember 52C, and a planet carrier member 52B that rotatable supports aset of planet gears 52D (only one of which is shown). The planet gears52D are each configured to intermesh with both the sun gear member 52Aand the ring gear member 52C. The sun gear member 52A is connected forcommon rotation with the transfer member 34. The ring gear member 52C isconnected for common rotation with the transmission output member 22.The planet carrier member 52B is connected for common rotation with thesecond interconnecting member 62.

The first brake 54 is selectively engageable to connect the second shaftor interconnecting member 62 with the transmission housing 14 in orderto restrict relative rotation of the member 62 and therefore the ringgear member 50A and the carrier member 52B. The second brake 56 isselectively engageable to connect the first shaft or interconnectingmember 60 with the transmission housing 14 in order to restrict relativerotation of the member 60 and therefore the sun gear member 50C. In FIG.5A, the clutch 58 is selectively engageable to connect the ring gearmember 50A and the carrier member 52B with the sun gear member 50C.Likewise, FIGS. 5B-4F illustrate stick diagrams of the correspondinggearbox arrangements 26B-26F which alter the location of the clutch 58,as described above.

Turning now to FIGS. 6A-F, another set of configurations of the gearbox26 are shown in lever diagram format. The gearboxes illustrated in FIGS.6A-F include specific types of transmissions known as stacked planetarygear sets, as will be described below. For example, the gearbox 26Gincludes a first planetary gear set 70 and a second planetary gear set72. The first planetary gear set 70 has three nodes: a first node 70A, asecond node 70B and a third node 70C. The second planetary gear set 72has three nodes: a first node 72A, a second node 72B and a third node72C.

The transfer member 34 is continuously coupled to the third node 70C ofthe first planetary gear set 70 or to the third node 72C of the secondplanetary gear set 72. The transmission output member 22 is coupled tothe first node 72A of the second planetary gear set 72. The second node70B of the first planetary gear set 70 is coupled to the second node 72Bof the second planetary gear set 72. The third node 70C of the firstplanetary gear set 70 is coupled to the third node 72C of the secondplanetary gear set 72.

A first brake 74 selectively connects the second node 70B of the firstplanetary gear set 70 and the second node 72B of the second planetarygear set 72 with a stationary member or transmission housing 14. Asecond brake 76 selectively connects the first node 70A of the firstplanetary gear set 70 with the stationary member or transmission housing14. A first clutch 78 selectively connects the third node 70C of thefirst planetary gear set 70 and the third node 72C of the secondplanetary gear set 72 with the first node 72A of the second planetarygear set 72 and the transmission output member 22.

With reference to FIG. 6B, an alternate gearbox arrangement 26H isshown. The gearbox 26H is similar to that shown in FIG. 6A and thereforelike components are indicated by like reference numbers. However, inFIG. 6B, the first clutch 78 is relocated and selectively connects thesecond node 70B of the first planetary gear set 70 and the second node72B of the second planetary gear set 72 with the first node 72A of thesecond planetary gear set 72 and the transmission output member 22

With reference to FIG. 6C, an alternate gearbox arrangement 26I isshown. The gearbox 26I is similar to that shown in FIG. 6A and thereforelike components are indicated by like reference numbers. However, inFIG. 6C, the first clutch 78 is relocated and selectively the secondnode 70B of the first planetary gear set 70 and the second node 72B ofthe second planetary gear set 72 with the third node 70C of the firstplanetary gear set 70 and the third node 72C of the second planetarygear set 72.

With reference to FIG. 6D, an alternate gearbox arrangement 26J isshown. The gearbox 26J is similar to that shown in FIG. 6A and thereforelike components are indicated by like reference numbers. However, inFIG. 6D, the first clutch 78 is relocated and selectively connects thesecond node 70B of the first planetary gear set 70 and the second node72B of the second planetary gear set 72 with the first node 70A of thefirst planetary gear set 70.

With reference to FIG. 6E, an alternate gearbox arrangement 26K isshown. The gearbox 26K is similar to that shown in FIG. 6A and thereforelike components are indicated by like reference numbers. However, inFIG. 6E, the first clutch 78 is relocated and selectively connects firstnode 70A of the first planetary gear set 70 with the first node 72A ofthe second planetary gear set 72.

With reference to FIG. 6F, an alternate gearbox arrangement 26L isshown. The gearbox 26L is similar to that shown in FIG. 6A and thereforelike components are indicated by like reference numbers. However, inFIG. 6F, the first clutch 78 is relocated and selectively connects thefirst node 70A of the first planetary gear set 70 with the third node70C of the first planetary gear set and the third node 72C of the secondplanetary gear set 72.

Turning now to FIGS. 7A-F, stick diagrams present schematic layouts ofembodiments of the gearbox 26G-L according to the present invention. InFIGS. 7A-F the numbering from the lever diagram of FIGS. 6A-F arecarried over. The clutches and couplings are correspondingly presentedwhereas the nodes of the planetary gear sets now appear as components ofplanetary gear sets such as sun gears, ring gears, planet gears andplanet gear carriers.

For example, the planetary gear set 70 and the planetary gear set 72 areconfigured as a stacked planetary gear set wherein the first planetarygear set 70 is nested radially inward of the second planetary gear set72. The planetary gear set 70 includes a sun gear member 70A, a ringgear member 70C, and a planet carrier member 70B that rotatably supportsa set of planet gears 70D (only one of which is shown). The planet gears70D are each configured to intermesh with both the sun gear member 70Aand the ring gear member 70C. The sun gear member 70A is connected forcommon rotation with a first shaft or interconnecting member 80. Thering gear member 70C is connected for common rotation with the transfermember 34. The planet carrier member 70B is connected for commonrotation with a second shaft or interconnecting member 82.

The planetary gear set 72 includes a sun gear member 72C, a ring gearmember 72A, and a planet carrier member 72B that rotatably supports aset of planet gears 72D (only one of which is shown). The planet gears72D are each configured to intermesh with both the sun gear member 72Cand the ring gear member 72A. The sun gear member 72C is connected forcommon rotation with the first shaft or interconnecting member 34. Thering gear member 72A is connected for common rotation with thetransmission output member 22. The planet carrier member 72B isconnected for common rotation with the second shaft or interconnectingmember 82. It should be appreciated that the ring gear member 70C of thefirst planetary gear set 70 and the sun gear member 72C of the secondplanetary gear set 72 may be formed from a single unitary member havinginner and outer gear teeth or from separate gears connected together forrotation.

The torque-transmitting mechanisms or brakes 74, 76 and clutch 78 allowfor selective interconnection of the shafts or interconnecting members,members of the planetary gear sets and the housing. Thetorque-transmitting mechanisms are friction, dog or synchronizer typemechanisms or the like. For example, the first brake 74 is selectivelyengageable to connect the second shaft or interconnecting member 82 withthe transmission housing 14 in order to restrict relative rotation ofthe member 82 and therefore the carrier member 70B of the firstplanetary gear set 70 and the carrier member 72B of the second planetarygear set 72. The second brake 76 is selectively engageable to connectthe first shaft or interconnecting member 80 with the transmissionhousing 14 in order to restrict relative rotation of the member 80 andtherefore the sun gear member 70A. In FIG. 7A, the clutch 78 isselectively engageable to connect the ring gear member 72A and thetransmission output shaft 22 with the transfer shaft 34 and the ringgear member 70C and sun gear member 72C. Likewise, FIGS. 7B-3Fillustrate stick diagrams of the corresponding gearbox arrangements26H-26L which alter the location of the clutch 78, as described above.

Turning now to FIGS. 8A-F, another set of configurations of the gearbox26 are shown in lever diagram format. The gearboxes illustrated in FIGS.8A-F include specific types of transmissions known as Simpson planetarygear sets, as will be described below. For example, the gearbox 26Mincludes a first planetary gear set 90 and a second planetary gear set92. The first planetary gear set 90 has three nodes: a first node 90A, asecond node 90B and a third node 90C. The second planetary gear set 92has three nodes: a first node 92A, a second node 92B and a third node92C.

The transfer member 34 is continuously coupled to the third node 90C ofthe first planetary gear set 90. The transmission output member 22 iscoupled to the second node 92B of the second planetary gear set 92. Thefirst node 90A of the first planetary gear set 90 is coupled to thefirst node 92A of the second planetary gear set 92. The second node 90Bof the first planetary gear set 90 is coupled to the third node 92C ofthe second planetary gear set 92.

A first brake 94 selectively connects the second node 90B of the firstplanetary gear set 90 and the third node 92C of the second planetarygear set 92 with a stationary member or transmission housing 14. Asecond brake 96 selectively connects the first node 90A of the firstplanetary gear set 90 and the first node 92A of the second planetarygear set with the stationary member or transmission housing 14. A firstclutch 98 selectively connects the first node 90A of the first planetarygear set 90 and the first node 92A of the second planetary gear set 92with the second node 90B of the first planetary gear set 90 and thethird node 92C of the second planetary gear set 92.

With reference to FIG. 8B, an alternate gearbox arrangement 26N isshown. The gearbox 26N is similar to that shown in FIG. 8A and thereforelike components are indicated by like reference numbers. However, inFIG. 8B, the first clutch 98 is relocated and selectively connects thefirst node 90A of the first planetary gear set 90 and the first node 92Aof the second planetary gear set 92 with the second node 92B of thesecond planetary gear set 92.

With reference to FIG. 8C, an alternate gearbox arrangement 26O isshown. The gearbox 26O is similar to that shown in FIG. 8A and thereforelike components are indicated by like reference numbers. However, inFIG. 8C, the first clutch 98 is relocated and selectively connects thesecond node 90B of the first planetary gear set 90 and the third node92C of the second planetary gear set 92 with the second node 92B of thesecond planetary gear set 92.

With reference to FIG. 8D, an alternate gearbox arrangement 26P isshown. The gearbox 26P is similar to that shown in FIG. 8A and thereforelike components are indicated by like reference numbers. However, inFIG. 8D, the first clutch 98 is relocated and selectively connects thesecond node 90B of the first planetary gear set 90 and the third node92C of the second planetary gear set 92 with the third node 90C of thefirst planetary gear set 90.

With reference to FIG. 8E, an alternate gearbox arrangement 26Q isshown. The gearbox 26Q is similar to that shown in FIG. 8A and thereforelike components are indicated by like reference numbers. However, inFIG. 8E, the first clutch 98 is relocated and selectively connects thefirst node 90A of the first planetary gear set 90 and the first node 92Aof the second planetary gear set 92 with the third node 90C of the firstplanetary gear set 90.

With reference to FIG. 8F, an alternate gearbox arrangement 26R isshown. The gearbox 26R is similar to that shown in FIG. 8A and thereforelike components are indicated by like reference numbers. However, inFIG. 8F, the first clutch 98 is relocated and selectively connects thethird node 90C of the first planetary gear set 90 with the second node92B of the second planetary gear set 92.

Turning now to FIGS. 9A-F, stick diagrams present schematic layouts ofembodiments of the gearbox 26M-R according to the present invention. InFIGS. 9A-F the numbering from the lever diagram of FIGS. 8A-F arecarried over. The clutches and couplings are correspondingly presentedwhereas the nodes of the planetary gear sets now appear as components ofplanetary gear sets such as sun gears, ring gears, planet gears andplanet gear carriers.

For example, the planetary gear set 90 includes a sun gear member 90A, aring gear member 90C, and a planet carrier member 90B that rotatablysupports a set of planet gears 90D (only one of which is shown). Theplanet gears 90D are each configured to intermesh with both the sun gearmember 90A and the ring gear member 90C. The sun gear member 90A isconnected for common rotation with a first shaft or interconnectingmember 100. The ring gear member 90C is connected for common rotationwith the transfer member 34. The planet carrier member 90B is connectedfor common rotation with a second shaft or interconnecting member 102.

The planetary gear set 92 includes a sun gear member 92A, a ring gearmember 92C, and a planet carrier member 92B that rotatably supports aset of planet gears 92D (only one of which is shown). The planet gears92D are each configured to intermesh with both the sun gear member 92Aand the ring gear member 92C. The sun gear member 92A is connected forcommon rotation with the first shaft or interconnecting member 100. Thering gear member 92C is connected for common rotation with the secondshaft or interconnecting member 102. The planet carrier member 92B isconnected for common rotation with the transmission output shaft 22.

The torque-transmitting mechanisms or brakes 94, 96 and clutch 98 allowfor selective interconnection of the shafts or interconnecting members,members of the planetary gear sets and the housing. Thetorque-transmitting mechanisms are friction, dog or synchronizer typemechanisms or the like. For example, the first brake 94 is selectivelyengageable to connect the second shaft or interconnecting member 102with the transmission housing 14 in order to restrict relative rotationof the member 102 and therefore the carrier member 90B of the firstplanetary gear set 90 and the ring gear member 92C of the secondplanetary gear set 92. The second brake 96 is selectively engageable toconnect the first shaft or interconnecting member 100 with thetransmission housing 14 in order to restrict relative rotation of themember 100 and therefore the sun gear member 90A and sun gear member92A. In FIG. 9A, the clutch 98 is selectively engageable to connect thering gear member 92C and the carrier member 90B with the sun gear member90A and the sun gear member 92A. Likewise, FIGS. 9B-3F illustrate stickdiagrams of the corresponding gearbox arrangements 26M-26R which alterthe location of the clutch 98, as described above.

It should be appreciated that where members of planetary gear sets orclutches and brakes are connected for common rotation they are directlyconnected for common rotation with no intervening torque transmittingdevices or planetary gear set members. However, it should be appreciatedthat individual interconnecting members may be formed of one or moremembers or integrally formed with members of the planetary gear setswithout departing from the scope of the present invention.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

The following is claimed:
 1. A powertrain for a motor vehiclecomprising: a transmission input member; a transmission output member;an intermediate member; a continuously variable unit having a firstpulley pair connected for common rotation with the transmission inputmember, a second pulley pair connected for common rotation with theintermediate member, and an endless member wrapped around the firstpulley pair and the second pulley pair; a first planetary gear setconnected to the intermediate member; a second planetary gear setconnected to the first planetary gear member and to the transmissionoutput member; a plurality of torque transmitting mechanismsinterconnected to the planetary gear arrangement; a chain driveconnected for common rotation with the transmission output member; atransfer member connected for common rotation with the chain drive; anda final drive planetary gear set connected for common rotation with thetransfer member, wherein selective engagement of the plurality of torquetransmitting mechanisms and selective movement of the first pulley andsecond pulley provides two forward ranges of continuous gear ratiosbetween the transmission input member and the transmission outputmember.
 2. The powertrain of claim 1 wherein the first planetary gearset and the second planetary gear sets each include a first member, asecond member, and a third member.
 3. The powertrain of claim 2 furthercomprising a first interconnecting member rotationally fixed to thefirst member of the first planetary gear set and the first member of thesecond planetary gear set.
 4. The powertrain of claim 3 furthercomprising a second interconnecting member rotationally fixed to thesecond member of the first planetary gear set and the third member ofthe second planetary gear set.
 5. The powertrain of claim 4 wherein theintermediate member is rotationally fixed to the third member of thefirst planetary gear set.
 6. The powertrain of claim 5 wherein thetransmission output member is rotationally fixed to the second member ofthe second planetary gear set.
 7. The powertrain of claim 6 wherein theplurality of torque transmitting mechanisms includes a first brake forselectively rotationally coupling the second member of the firstplanetary gear set and the third member of the second planetary gear setto a stationary member.
 8. The powertrain of claim 7 wherein theplurality of torque transmitting mechanisms includes a second brake forselectively rotationally coupling the first member of the firstplanetary gear set and the first member of the second planetary gear setto the stationary member.
 9. The powertrain of claim 8 wherein theplurality of torque transmitting mechanisms includes a clutch forselectively rotationally coupling at least one of the first, second, andthird members of the first planetary gear set with at least one of thefirst, second, and third members of the second planetary gear set. 10.The powertrain of claim 9 wherein the clutch selectively rotationallycouples the first member of the first planetary gear set and the firstmember of the second planetary gear set with the second member of thefirst planetary gear set and the third member of the second planetarygear set.
 11. The powertrain of claim 9 wherein the clutch selectivelyrotationally couples the first member of the first planetary gear setand the first member of the second planetary gear set with the secondmember of the second planetary gear set.
 12. The powertrain of claim 9wherein the clutch selectively rotationally couples the second member ofthe second planetary gear set with the second member of the firstplanetary gear set and the third member of the second planetary gearset.
 13. The powertrain of claim 9 wherein the clutch selectivelyrotationally couples the third member of the first planetary gear setwith the second member of the first planetary gear set and the thirdmember of the second planetary gear set.
 14. The powertrain of claim 9wherein the clutch selectively rotationally couples the first member ofthe first planetary gear set and the first member of the secondplanetary gear set with the third member of the first planetary gearset.
 15. The powertrain of claim 9 wherein the clutch selectivelyrotationally couples the third member of the first planetary gear setwith the second member of the second planetary gear set.
 16. Thepowertrain of claim 9 wherein the first members are sun gear members,the second members are planet carrier members, and the third members arering gear members.
 17. The powertrain of claim 1 wherein the final driveplanetary gear set includes a fifth member, a sixth member, and aseventh member, wherein the fifth member is connected for commonrotation with the transfer member, the sixth member is interconnected toroad wheels of the motor vehicle, and the seventh member is connected toa stationary member.
 18. The powertrain of claim 17 wherein the fifthmember of the final drive planetary gear set is a sun gear, the sixthmember of the final drive planetary gear set is a planet carrier member,and the seventh member of the final drive planetary gear set is a ringgear.
 19. A powertrain for a motor vehicle comprising: a transmissioninput member; a transmission output member; an intermediate member; acontinuously variable unit having a first pulley pair connected forcommon rotation with the transmission input member, a second pulley pairconnected for common rotation with the intermediate member, and anendless member wrapped around the first pulley pair and the secondpulley pair; a first planetary gear set having first, second, and thirdmembers, wherein the third member of the first planetary gear set isconnected to the intermediate member; a second planetary gear set havingfirst, second, and third members, wherein the second member of thesecond planetary gear set is connected to the transmission outputmember; a first interconnecting member rotationally fixed to the firstmember of the first planetary gear set and the first member of thesecond planetary gear set; a second interconnecting member rotationallyfixed to the second member of the first planetary gear set and the thirdmember of the second planetary gear set; a first brake for selectivelyrotationally coupling the second member of the first planetary gear setand the third member of the second planetary gear set to a stationarymember; a second brake for selectively rotationally coupling the firstmember of the first planetary gear set and the first member of thesecond planetary gear set to the stationary member; a clutch forselectively rotationally coupling at least one of the first, second, andthird members of the first planetary gear set with at least one of thefirst, second, and third members of the second planetary gear set; achain drive connected for common rotation with the transmission outputmember; a transfer member connected for common rotation with the chaindrive; and a final drive planetary gear set connected for commonrotation with the transfer member, wherein selective engagement of thefirst brake, the second brake, and the clutch and selective movement ofthe first pulley and second pulley provides two forward ranges ofcontinuous gear ratios between the transmission input member and thetransmission output member.
 20. A powertrain for a motor vehiclecomprising: a transmission input member; a transmission output member;an intermediate member; a continuously variable unit having a firstpulley pair connected for common rotation with the transmission inputmember, a second pulley pair connected for common rotation with theintermediate member, and an endless member wrapped around the firstpulley pair and the second pulley pair; a first planetary gear sethaving a sun gear, a planet carrier, and a ring gear, wherein the ringgear of the first planetary gear set is connected to the intermediatemember; a second planetary gear set having a sun gear, a planet carrier,and a ring gear, wherein the planet carrier of the second planetary gearset is connected to the transmission output member; a firstinterconnecting member rotationally fixed to the sun gear of the firstplanetary gear set and the sun gear of the second planetary gear set; asecond interconnecting member rotationally fixed to the planet carrierof the first planetary gear set and ring gear of the second planetarygear set; a first brake for selectively rotationally coupling the planetcarrier of the first planetary gear set and the ring gear of the secondplanetary gear set to a stationary member; a second brake forselectively rotationally coupling the sun gear of the first planetarygear set and the sun gear of the second planetary gear set to thestationary member; a clutch for selectively rotationally coupling atleast one of the sun gear, planet carrier, and ring gear of the firstplanetary gear set with at least one of the sun gear, planet carrier,and ring gear of the second planetary gear set; a chain drive connectedfor common rotation with the transmission output member; a transfermember connected for common rotation with the chain drive; and a finaldrive planetary gear set connected for common rotation with the transfermember, wherein selective engagement of the first brake, the secondbrake, and the clutch and selective movement of the first pulley andsecond pulley provides two forward ranges of continuous gear ratiosbetween the transmission input member and the transmission outputmember.